The overall objective is to provide information on the type and probability of normal tissue damage from intraoperative irradiation as compared to more conventional irradiation protocols. The interest in intraoperative therapy was stimulated because of difficulty in delivering adequate radiation doses to tumors located near critical radiosensitive organs or tissues. Tumors adjacent to or including major blood vessels are difficult to completely excise surgically. The aim of this study is to determine early and late response of canine paraaortic tissues to large single doses of radiation alone, following fractionated external beam irradiation or combined with other modalities such as hyperthermia or radioprotectors. Sequential examinations will include arteriograms, intravenous urography, blood and urine chemistries, observations for spinal cord injury and electrophysiologic measurements. Necropsies at 6 months to 4 years will provide tissues for morphometric analysis of kidney, spinal cord, bladder and large vessels. Of particular interest will be the percentage volume changes in parenchyma, microvasculature and connective tissue.